express res.download serving up 0 byte files - node.js

Question

res.download is serving up the file but once downloaded it is 0 bytes?
Any ideas?
app.get('/download', function(req, res) {
console.log("download");
console.log(req.query.fileID);
fileDownload(req.query.fileID, function(rep){
if(rep.success){
console.log("Serving File to User, File: " + rep.data);
res.download(__dirname + "/" + rep.data, rep.data)
}else{
console.log(res);
}
});
})
A ls on the folder shows the file is there ready for download, the names are correct and all on download box that browser displays but download is always 0 bytes in size.
A check on the file from file file download shoes yes it is there and yes its all good.
ISSUE FOUND MAYBE:
I Think the issue is the file is not fully downloaded before its being served to client, see below,i will try adding a callback to the PIPE.....
function fileDownload(id, callback){
info(id, function(res){
if(!res.error){
info(id, function(res){
if(!res.error){
//console.log(res.data);
var d = JSON.parse(res.data);
//console.log(d['file_name']);
var url2 = baseurl + "/api/file/" + id ;
var r = request(url2);
r.on('response', function (res) {
res.pipe(fs.createWriteStream('./' + d['id'] + d['file_name']));
console.log("Download Done: " + './' + d['id'] + d['file_name']);
return callback({success:true, data:d['id'] + d['file_name']});
});
}else{
console.log("ERROR: " + res.data)
return callback({success:false, data: res.data});
}
});
}else{
console.log("ERROR: " + res.data)
return callback({success:false, data: res.data});
}
});
};

Answer 1

The issue was due to the file being served up before the stream was finished writing,
fix add .on('close') to the stream.
r.on('response', function (res) {
res.pipe(fs.createWriteStream('./' + d['id'] + d['file_name']).on('close', function() {
console.log('file done');
console.log("Download Done: " + './' + d['id'] + d['file_name']);
return callback({success:true, data:d['id'] + d['file_name']});
}));
console.log("You should not see this");
});